(function(global) {
  'use strict';
  var global = global || {};
  var _Base64 = global.Base64;
  var version = "1.0.0";
  var buffer;
  var b64chars = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/';
  var b64tab = function(bin) {
      var t = {};
      for (var i = 0, l = bin.length; i < l; i++) t[bin.charAt(i)] = i;
      return t;
  }(b64chars);
  var fromCharCode = String.fromCharCode;
  var cb_utob = function(c) {
      if (c.length < 2) {
          var cc = c.charCodeAt(0);
          return cc < 0x80 ? c :
              cc < 0x800 ? (fromCharCode(0xc0 | (cc >>> 6)) +
                  fromCharCode(0x80 | (cc & 0x3f))) :
              (fromCharCode(0xe0 | ((cc >>> 12) & 0x0f)) +
                  fromCharCode(0x80 | ((cc >>> 6) & 0x3f)) +
                  fromCharCode(0x80 | (cc & 0x3f)));
      } else {
          var cc = 0x10000 +
              (c.charCodeAt(0) - 0xD800) * 0x400 +
              (c.charCodeAt(1) - 0xDC00);
          return (fromCharCode(0xf0 | ((cc >>> 18) & 0x07)) +
              fromCharCode(0x80 | ((cc >>> 12) & 0x3f)) +
              fromCharCode(0x80 | ((cc >>> 6) & 0x3f)) +
              fromCharCode(0x80 | (cc & 0x3f)));
      }
  };
  var re_utob = /[\uD800-\uDBFF][\uDC00-\uDFFFF]|[^\x00-\x7F]/g;
  var utob = function(u) {
      return u.replace(re_utob, cb_utob);
  };
  var cb_encode = function(ccc) {
      var padlen = [0, 2, 1][ccc.length % 3],
          ord = ccc.charCodeAt(0) << 16 |
          ((ccc.length > 1 ? ccc.charCodeAt(1) : 0) << 8) |
          ((ccc.length > 2 ? ccc.charCodeAt(2) : 0)),
          chars = [
              b64chars.charAt(ord >>> 18),
              b64chars.charAt((ord >>> 12) & 63),
              padlen >= 2 ? '=' : b64chars.charAt((ord >>> 6) & 63),
              padlen >= 1 ? '=' : b64chars.charAt(ord & 63)
          ];
      return chars.join('');
  };
  var btoa = global.btoa ? function(b) {
      return global.btoa(b);
  } : function(b) {
      return b.replace(/[\s\S]{1,3}/g, cb_encode);
  };
  var _encode = buffer ? function(u) {
          return (u.constructor === buffer.constructor ? u : new buffer(u))
              .toString('base64')
      } :
      function(u) { return btoa(utob(u)) };
  var encode = function(u, urisafe) {
      return !urisafe ?
          _encode(String(u)) :
          _encode(String(u)).replace(/[+\/]/g, function(m0) {
              return m0 == '+' ? '-' : '_';
          }).replace(/=/g, '');
  };
  var encodeURI = function(u) { return encode(u, true) };
  var re_btou = new RegExp([
      '[\xC0-\xDF][\x80-\xBF]',
      '[\xE0-\xEF][\x80-\xBF]{2}',
      '[\xF0-\xF7][\x80-\xBF]{3}'
  ].join('|'), 'g');
  var cb_btou = function(cccc) {
      switch (cccc.length) {
          case 4:
              var cp = ((0x07 & cccc.charCodeAt(0)) << 18) |
                  ((0x3f & cccc.charCodeAt(1)) << 12) |
                  ((0x3f & cccc.charCodeAt(2)) << 6) |
                  (0x3f & cccc.charCodeAt(3)),
                  offset = cp - 0x10000;
              return (fromCharCode((offset >>> 10) + 0xD800) +
                  fromCharCode((offset & 0x3FF) + 0xDC00));
          case 3:
              return fromCharCode(
                  ((0x0f & cccc.charCodeAt(0)) << 12) |
                  ((0x3f & cccc.charCodeAt(1)) << 6) |
                  (0x3f & cccc.charCodeAt(2))
              );
          default:
              return fromCharCode(
                  ((0x1f & cccc.charCodeAt(0)) << 6) |
                  (0x3f & cccc.charCodeAt(1))
              );
      }
  };
  var btou = function(b) {
      return b.replace(re_btou, cb_btou);
  };
  var cb_decode = function(cccc) {
      var len = cccc.length,
          padlen = len % 4,
          n = (len > 0 ? b64tab[cccc.charAt(0)] << 18 : 0) |
          (len > 1 ? b64tab[cccc.charAt(1)] << 12 : 0) |
          (len > 2 ? b64tab[cccc.charAt(2)] << 6 : 0) |
          (len > 3 ? b64tab[cccc.charAt(3)] : 0),
          chars = [
              fromCharCode(n >>> 16),
              fromCharCode((n >>> 8) & 0xff),
              fromCharCode(n & 0xff)
          ];
      chars.length -= [0, 0, 2, 1][padlen];
      return chars.join('');
  };
  var atob = global.atob ? function(a) {
      return global.atob(a);
  } : function(a) {
      return a.replace(/[\s\S]{1,4}/g, cb_decode);
  };
  var _decode = buffer ? function(a) {
          return (a.constructor === buffer.constructor ?
              a : new buffer(a, 'base64')).toString();
      } :
      function(a) { return btou(atob(a)) };
  var decode = function(a) {
      return _decode(
          String(a).replace(/[-_]/g, function(m0) { return m0 == '-' ? '+' : '/' })
          .replace(/[^A-Za-z0-9\+\/]/g, '')
      );
  };
  var noConflict = function() {
      var Base64 = global.Base64;
      global.Base64 = _Base64;
      return Base64;
  };
  global.Base64 = {
      VERSION: version,
      atob: atob,
      btoa: btoa,
      fromBase64: decode,
      toBase64: encode,
      utob: utob,
      encode: encode,
      encodeURI: encodeURI,
      btou: btou,
      decode: decode,
      noConflict: noConflict
  };
  // if ES5 is available, make Base64.extendString() available
  if (typeof Object.defineProperty === 'function') {
      var noEnum = function(v) {
          return { value: v, enumerable: false, writable: true, configurable: true };
      };
      global.Base64.extendString = function() {
          Object.defineProperty(
              String.prototype, 'fromBase64', noEnum(function() {
                  return decode(this)
              }));
          Object.defineProperty(
              String.prototype, 'toBase64', noEnum(function(urisafe) {
                  return encode(this, urisafe)
              }));
          Object.defineProperty(
              String.prototype, 'toBase64URI', noEnum(function() {
                  return encode(this, true)
              }));
      };
  }
  module.exports = global.Base64;
})(this);

